When Randy Rusk's father returned from World War II, and began the family ranch, Rusk Ranches, near Westcliffe, Colo., the only cattle that could survive, let alone thrive, at the 9,000 feet and higher elevation were Herefords.

Rusk said his family dealt with the bad eyes and bad bags common to Herefords in that day because the tradeoff of live cattle was essential. High Altitude Disease is central to the management decisions Rusk and his son, Tate, make in terms of bull selection and replacement female selection. Cattle affected by the disease succumb to heart failure when stressed at high altitude.

Prior to routinely Pulmonary Anterior Pressure testing bulls and females, Rusk said the losses were crippling. As PAP testing became more popular, Rusk was able to purchase bulls from Shane Temple at T Heart Cattle Company and Willie Altenberg, two breeders he said have lead the way in developing high-altitude cattle.

"You can't afford to have problems," he said. "We run a lot of outside cattle also and in the old days, we couldn't find much for low-PAP cattle for summer pasture cattle. We had to develop a whole new program for how we handle brisket cattle."

High Altitude Disease, or brisket, he said, is an accumulative disease that happens over a period of time that worsens the longer cattle are kept at high altitude. To make their outside cattle operation, paid upon gain, profitable, Rusk said they redesigned it to run more cattle for a shorter period of time and then move them to lower altitude prior to them experiencing cardiac symptoms. Prior to perfecting their system, Rusk might have losses of more than 40 individuals for every 1,000 head. Now, he and his son calve 700 cows and he said they may have one symptomatic individual.

He moved away from Herefords but maintained a red-hided herd, moving to Red Angus and eventually purchasing Simmental bulls that have traditionally been well-suited to altitude.

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"There's probably as much variation within a breed as there is between breeds," he said. "The original Simmental bulls that came over were great big, heavy, growthy bulls that put me in business."

At the time, Rusk was calving heifers for other cattlemen and the bulls caused him a number of calving problems. However, heritable traits, he said, are those that can be selected for or against and by choosing lower birth weights, cattlemen kept the growth without the calving problems. The same held true for Hereford cattle used at high altitude, he said. Rather than choosing heavy milking cattle, selecting cattle who put less energy into milk production and more emphasis on efficiency.

"We've done a good job with the Simmentals," he said. "We've made them real workable for the American cattleman from lower elevations to my elevation with the help of Willie (Altenberg) and Shane (Temple) trying to find low-PAP bulls that will work at elevation. They've done a good job, the cattle work well for us."

T HEART RANCH

There's a postcard gathering dust on the dashboard of Shane Temple's pickup. The card advertises a bull sale offering bulls that were PAP tested for high-altitude performance. Temple has been stewing a bit over the advertisement as the bulls were PAP tested below 4,000 feet of altitude.

Temple has built his business, T Heart Ranch, La Garita, Colo., by PAP testing generations of cattle to offer customers extensive data to drive their decisions as they purchase heifers and bulls that will perform at high altitudes. Temple tests sale cattle under the most ideal test conditions — post weaning and prior to the sale while having been developed at high altitudes, which in Temple's case is no lower than 7,680 feet.

"A PAP test is not a true PAP test unless it's done at elevation," he said. "It is so important to buy true high-altitude cattle, those who are at over 7,500 feet of elevation. Their mothers, their mother's mothers, their great-grandmothers have all experienced high elevation and we have weeded out the weak ones."

Several years ago, Temple, in an effort to sample new genetics, bred 40-45 heifers to a new bull. He said they calved the heifers and noticed the calves were a bit slower than their counterparts and demonstrated less vigor. After two weeks, he had lost 20 of the calves to High Altitude Disease.

"We cut them open and their hearts were the size of softballs or bigger," he said. "We lost 20 head there. That's how devastating this is."

Temple places high priority on PAP testing cattle and doing so saves him money preventing losses in his own operation but also for his customers.

"In the next bull sale catalog, we'll be able to offer our customers a PAP test on the bull, a PAP test on his mother, his grandmother, his great grandmother, the sire … they'll get information on seven or eight animals when they look at that one bull," he said. "And it's a test from 7,860 feet so it's a good test."

In preparation for their March bull sale, the Temple family is sorting through 300 bulls to choose the top 200 or so. Most of his customers are high-altitude cattlemen though he is gaining new customers in Nebraska and Oklahoma who appreciate the performance of the high-altitude cattle.

Purchasing replacement females is difficult for those whose environments demand high-altitude cattle and making those females available to buyers is one portion of Temple's business, a December replacement female sale. Females for the sale are chosen from Temple's 1,000-head cow herd and also purchased from the top end of his bull buyers' calf crops. Females are then developed, AI bred, fetal sexed and the top end is offered in the sale.

Cattle that are not in danger of heart failure but PAP test high, which for Temple's elevation is 47 or higher, are offered to lower altitude ranchers. Temple utilizes Simmental genetics, a breed that has traditionally performed well at altitude. The SimAngus cross is proving its performance for the operation.

"They're an all around good beef cow," he said. "You can make good mamas with them, they're excellent in the feedlot, they scan well, they marble well, they work well in the elevation for us and they're good all around. Any direction you want to go, they'll work."

Testing Done Right

Tim Holt, DVM, is the arguable expert on PAP testing. After 19 years in private practice, he joined the Colorado State University faculty and continues the work testing high-altitude cattle that he began in 1980. Holt explained that some low-altitude producers PAP test cattle, especially bulls, but those results lack repeatability. Bulls PAP tested at low altitude, he said, must be sent to high altitude for no fewer than three to six weeks and retested with high-test cattle sent back to low altitude and not retained.

"We have the opportunity to rule out or cull or at least mark those bulls that can not be used at altitude," he said. "So (when cattle are tested at low altitude) what we're doing is finding those hyperreactive bulls and that's important to everybody."

PAP tests at low altitude lack the repeatability of tests performed on cattle at altitude for more than six weeks, making it vital that high-altitude producers retest those cattle after altitude exposure. Even cattle that score below a 40 on low-altitude tests, may prove to be high risk at altitude.

"If I go to Brush or I go to Wheatland and buy a 39, I have a 70 percent chance of that bull remaining in that low-risk category," Holt said.

Holt recommends cattle tested below 6,000 feet be rechecked at altitude. As a rule of thumb, Holt said a 41 and under are typically classified as low risk taking into consideration age, and elevation tested for the best results.

High Altitude Disease and Hardware Disease present similarly and can be differentiated through a necropsy. In Hardware Disease, Holt said, the heart is compromised by infection leading to heart failure. Cattle suffering from both diseases will present with exercise intolerance, enlarged jugular veins, swelling in the brisket area and general lethargy. A necropsy on a High Altitude Disease individual will reveal an enlarged liver, an abdomen filled with fluid, a round and floppy heart with a thin heart. A necropsy of a hardware disease individual will reveal a pus-filled cavity and fibrin around the heart.

With nearly 40 years studying High Altitude Disease, Holt is still driven by his deep interest and, he said, his admiration for the people he works with. He has worked with producers, like the Rusk family, who used to experience significant losses and now lose very few. That benefits their operation and keeps Holt motivated.

"If I can make that type of difference in the cattle industry and help people that I care for so much, that's why I do it," he said. 

— Gabel is a freelance writer from Wiggins, Colo., where she and her family raise cattle and show goats. She can be reached at rachelspencermedia@gmail.com or on Facebook at Rachel Spencer Media.